Day 1

AdventOfCode/AdventOfCode.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
 	<OutputType>Exe</OutputType>
-	<TargetFramework>net8.0</TargetFramework>
+	<TargetFramework>net9.0</TargetFramework>
 	<ImplicitUsings>enable</ImplicitUsings>
 	<Nullable>enable</Nullable>
   </PropertyGroup>

AdventOfCode/Problems/AOC2024/Day1/HistorianHysteria.cs

@@ -0,0 +1,40 @@
+using AdventOfCode.Runner.Attributes;
+
+using System;
+using System.Collections.Frozen;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AdventOfCode.Problems.AOC2024.Day1;
+[ProblemInfo(2024, 1, "Historian Hysteria")]
+internal class HistorianHysteria : Problem<int, int>
+{
+	private int[] _left = [];
+	private int[] _right = [];
+
+	public override void CalculatePart1()
+	{
+		Part1 = _left.Order()
+			.Zip(_right.Order())
+			.Select(a => Math.Abs(a.First - a.Second))
+			.Sum();
+	}
+
+	public override void CalculatePart2()
+	{
+		var rightFeq = _right.GroupBy(x => x)
+			.ToFrozenDictionary(g => g.Key, g => g.Count());
+		Part2 = _left.Select(x => rightFeq.TryGetValue(x, out var f) ? f * x : 0)
+			.Sum();
+	}
+
+	public override void LoadInput()
+	{
+		var lines = ReadInputLines("input.txt");
+		var data = lines.Select(l => l.Split(' ').Select(int.Parse)).ToList();
+		_left = data.Select(l => l.First()).ToArray();
+		_right = data.Select(l => l.Last()).ToArray();
+	}
+}